Impeller with offset splitter blades

ABSTRACT

An impeller includes a hub mountable to a rotary shaft and configured to rotate about a center axis. The impeller may include a plurality of main blades and splitter blades arranged equidistantly and circumferentially about the center axis. A splitter blade having a leading edge and a trailing edge may be positioned between first and second adjacent main blades and canted such that the leading edge is displaced from a blade position equidistant the first and second adjacent main blades a first percentage amount of one half an angular distance between the first and second adjacent main blades. The trailing edge may be displaced from the blade position equidistant the first and second adjacent main blades a second percentage amount of one half the angular distance between the first and second adjacent main blades. The second percentage amount may be greater or less than the first percentage amount.

BACKGROUND

This application claims the benefit of U.S. Provisional PatentApplication having Ser. No. 62/139,032, which was filed Mar. 27, 2015.The aforementioned patent application is hereby incorporated byreference in its entirety into the present application to the extentconsistent with the present application.

STATEMENT OF GOVERNMENT INTEREST

This invention was made with government support under GovernmentContract No. DOE-DE-FE0000493 awarded by the U.S. Department of Energy.The government has certain rights in the invention.

Compressors and systems including compressors have been developed andare utilized in a myriad of industrial processes (e.g., petroleumrefineries, offshore oil production platforms, and subsea processcontrol systems) to compress gas, typically by applying mechanicalenergy to the gas in a low pressure environment and transporting the gasand compressing the gas to a higher pressure environment. The compressedgas may be utilized to perform work or as an element in the operation ofone or more downstream process components. As conventional compressorsare increasingly used in offshore oil production facilities and otherenvironments facing space constraints, there is an ever-increasingdemand for smaller, lighter, and more compact compressors. In additionto the foregoing, it is desirable for commercial purposes that thecompact compressors achieve higher compression ratios (e.g., 10:1 orgreater) while optimizing efficiency and maintaining a compactarrangement.

In view of the foregoing, skilled artisans have proposed approaches toimprove the efficiency of the compact compressors, many of which in thecase of compact centrifugal compressors relate to the blading of one ormore impellers operating therein. One such approach has included the useof splitter blades mounted to the impeller, such that each splitterblade is disposed equidistantly between adjacent full blades mounted toand extending from the hub of the impeller; however, such an approachhas been determined to result in unequal mass flow in channels formedbetween the splitter blades and the adjacent full blades, thus resultingin efficiency losses.

What is needed, therefore, is an efficient compression system thatprovides increased compression ratios in a compact arrangement that iseconomically and commercially viable.

SUMMARY

Embodiments of the disclosure may provide an impeller for a compressor.The impeller may include a hub mountable to a rotary shaft of thecompressor and configured to rotate about a center axis. The hub mayinclude a first meridional end portion and a second meridional endportion. The impeller may also include a plurality of main bladesmounted to or integral with the hub. The plurality of main blades may bearranged equidistantly and circumferentially about the center axis. Theimpeller may further include a plurality of splitter blades mounted toor integral with the hub. The plurality of splitter blades may bearranged equidistantly and circumferentially about the center axis. Eachsplitter blade may include a leading edge meridionally spaced from thefirst meridional end portion and a trailing edge proximal the secondmeridional end portion. A splitter blade may be positioned between afirst adjacent main blade and a second adjacent main blade and cantedsuch that the leading edge of the splitter blade is displaced from ablade position equidistant the first adjacent main blade and the secondadjacent main blade a first percentage amount of one half an angulardistance between the first adjacent main blade and the second adjacentmain blade. The trailing edge of the splitter blade may be displacedfrom the blade position equidistant the first adjacent main blade andthe second adjacent main blade a second percentage amount of one halfthe angular distance between the first adjacent main blade and thesecond adjacent main blade. The second percentage amount may be greateror less than the first percentage amount.

Embodiments of the disclosure may further provide a compressor. Thecompressor may include a housing and an inlet coupled to or integralwith the housing and defining an inlet passageway configured to receiveand flow a process fluid. The compressor may also include a rotary shaftconfigured to be driven by a driver, and a centrifugal impeller coupledwith the rotary shaft and fluidly coupled to the inlet passageway. Thecentrifugal impeller may be configured to rotate about a center axis andimpart energy to the process fluid received via the inlet passageway.The centrifugal impeller may include a hub defining a borehole throughwhich a coupling member or the rotary shaft of the supersonic compressorextends. The hub may include a first meridional end portion having anannular portion and a second meridional end portion forming adisc-shaped portion. The centrifugal impeller may also include aplurality of blades mounted to or integral with the hub. The pluralityof blades may be arranged equidistantly and circumferentially about thecenter axis and include a splitter blade positioned between a firstadjacent main blade and a second adjacent main blade and canted withrespect to the first adjacent main blade and the second adjacent mainblade. The compressor may further include a static diffusercircumferentially disposed about the centrifugal impeller and configuredto receive the process fluid from the centrifugal impeller and convertthe energy imparted to pressure energy. The compressor may also includea collector fluidly coupled to and configured to collect the processfluid exiting the static diffuser, such that the compressor isconfigured to provide a compression ratio of at least about 8:1.

Embodiments of the disclosure may further provide a compression system.The compression system may include a driver including a drive shaft. Thedriver may be configured to provide the drive shaft with rotationalenergy. The compression system may also include a supersonic compressoroperatively coupled to the driver via a rotary shaft integral with orcoupled with the drive shaft and configured to rotate about a centeraxis. The supersonic compressor may include a compressor chassis and aninlet defining an inlet passageway configured to flow a process fluidtherethrough. The process fluid may have a first velocity and a firstpressure energy. The supersonic compressor may further include acentrifugal impeller coupled with the rotary shaft and fluidly coupledto the inlet passageway. The centrifugal impeller may have a tip and maybe configured to increase the first velocity and the first pressureenergy of the process fluid received via the inlet passageway anddischarge the process fluid from the tip in at least a partially radialdirection having a second velocity and a second pressure energy. Thesecond velocity may be a supersonic velocity having an absolute Machnumber of about one or greater. The centrifugal impeller may include ahub defining a borehole through which a coupling member or the rotaryshaft of the supersonic compressor extends. The hub may include a firstmeridional end portion having an annular portion and a second meridionalend portion forming the tip. The centrifugal impeller may also include aplurality of blades mounted to or integral with the hub. The pluralityof blades may be arranged equidistantly and circumferentially about thecenter axis and include a splitter blade positioned between a firstadjacent main blade and a second adjacent main blade and canted withrespect to the first adjacent main blade and the second adjacent mainblade. The supersonic compressor may also include a static diffusercircumferentially disposed about the tip of the centrifugal impeller anddefining an annular diffuser passageway configured to receive and reducethe second velocity of the process fluid to a third velocity andincrease the second pressure energy to a third pressure energy, thethird velocity being a subsonic velocity. The supersonic compressor mayfurther include a discharge volute fluidly coupled to the annulardiffuser passageway and configured to receive the process fluid flowingtherefrom, such that the supersonic compressor is configured to providea compression ratio of at least about 8:1.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying Figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale. In fact, the dimensions of the variousfeatures may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 illustrates a schematic view of an exemplary compression system,according to one or more embodiments.

FIG. 2 illustrates a cross-sectional view of an exemplary compressor,which may be included in the compression system of FIG. 1, according toone or more embodiments.

FIG. 3A illustrates a perspective view of an exemplary impeller, whichmay be included in the compressor of FIG. 2, according to one or moreembodiments.

FIG. 3B illustrates a front view of the impeller of FIG. 3A, accordingto one or more embodiments.

DETAILED DESCRIPTION

It is to be understood that the following disclosure describes severalexemplary embodiments for implementing different features, structures,or functions of the invention. Exemplary embodiments of components,arrangements, and configurations are described below to simplify thepresent disclosure; however, these exemplary embodiments are providedmerely as examples and are not intended to limit the scope of theinvention. Additionally, the present disclosure may repeat referencenumerals and/or letters in the various exemplary embodiments and acrossthe Figures provided herein. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various exemplary embodiments and/or configurationsdiscussed in the various Figures. Moreover, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed interposing the first and second features, suchthat the first and second features may not be in direct contact.Finally, the exemplary embodiments presented below may be combined inany combination of ways, i.e., any element from one exemplary embodimentmay be used in any other exemplary embodiment, without departing fromthe scope of the disclosure.

Additionally, certain terms are used throughout the followingdescription and claims to refer to particular components. As one skilledin the art will appreciate, various entities may refer to the samecomponent by different names, and as such, the naming convention for theelements described herein is not intended to limit the scope of theinvention, unless otherwise specifically defined herein. Further, thenaming convention used herein is not intended to distinguish betweencomponents that differ in name but not function. Additionally, in thefollowing discussion and in the claims, the terms “including” and“comprising” are used in an open-ended fashion, and thus should beinterpreted to mean “including, but not limited to.” All numericalvalues in this disclosure may be exact or approximate values unlessotherwise specifically stated. Accordingly, various embodiments of thedisclosure may deviate from the numbers, values, and ranges disclosedherein without departing from the intended scope. Furthermore, as it isused in the claims or specification, the term “or” is intended toencompass both exclusive and inclusive cases, i.e., “A or B” is intendedto be synonymous with “at least one of A and B,” unless otherwiseexpressly specified herein.

FIG. 1 illustrates a schematic view of an exemplary compression system100, according to one or more embodiments. The compression system 100may include one or more compressors 102 (one is shown) configured topressurize a process fluid. In an exemplary embodiment, the compressionsystem 100 may have a compression ratio of at least about 6:1 orgreater. For example, the compression system 100 may compress theprocess fluid to a compression ratio of about 6:1, about 6.1:1, about6.2:1, about 6.3:1, about 6.4:1, about 6.5:1, about 6.6:1, about 6.7:1,about 6.8:1, about 6.9:1, about 7:1, about 7.1:1, about 7.2:1, about7.3:1, about 7.4:1, about 7.5:1, about 7.6:1, about 7.7:1, about 7.8:1,about 7.9:1, about 8:1, about 8.1:1, about 8.2:1, about 8.3:1, about8.4:1, about 8.5:1, about 8.6:1, about 8.7:1, about 8.8:1, about 8.9:1,about 9:1, about 9.1:1, about 9.2:1, about 9.3:1, about 9.4:1, about9.5:1, about 9.6:1, about 9.7:1, about 9.8:1, about 9.9:1, about 10:1,about 10.1:1, about 10.2:1, about 10.3:1, about 10.4:1, about 10.5:1,about 10.6:1, about 10.7:1, about 10.8:1, about 10.9:1, about 11:1,about 11.1:1, about 11.2:1, about 11.3:1, about 11.4:1, about 11.5:1,about 11.6:1, about 11.7:1, about 11.8:1, about 11.9:1, about 12:1,about 12.1:1, about 12.2:1, about 12.3:1, about 12.4:1, about 12.5:1,about 12.6:1, about 12.7:1, about 12.8:1, about 12.9:1, about 13:1,about 13.1:1, about 13.2:1, about 13.3:1, about 13.4:1, about 13.5:1,about 13.6:1, about 13.7:1, about 13.8:1, about 13.9:1, about 14:1, orgreater.

The compression system 100 may also include, amongst other components, adriver 104 operatively coupled to the compressor 102 via a drive shaft106. The driver 104 may be configured to provide the drive shaft 106with rotational energy. In an exemplary embodiment, the drive shaft 106may be integral with or coupled with a rotary shaft 108 of thecompressor 102, such that the rotational energy of the drive shaft 106is imparted to the rotary shaft 108. The drive shaft 106 may be coupledwith the rotary shaft 108 via a gearbox (not shown) including aplurality of gears configured to transmit the rotational energy of thedrive shaft 106 to the rotary shaft 108 of the compressor 102, such thatthe drive shaft 106 and the rotary shaft 108 may spin at the same speed,substantially similar speeds, or differing speeds and rotationaldirections.

The driver 104 may be a motor and more specifically may be an electricmotor, such as a permanent magnet motor, and may include a stator (notshown) and a rotor (not shown). It will be appreciated, however, thatother embodiments may employ other types of electric motors including,but not limited to, synchronous motors, induction motors, and brushed DCmotors. The driver 104 may also be a hydraulic motor, an internalcombustion engine, a steam turbine, a gas turbine, or any other devicecapable of driving the rotary shaft 108 of the compressor 102 eitherdirectly or through a power train.

In an exemplary embodiment, the compressor 102 may be a direct-inletcentrifugal compressor. In other embodiments, the compressor 102 may bea back-to-back compressor. The direct-inlet centrifugal compressor maybe, for example, a version of a Dresser-Rand Pipeline Direct Inlet (PDI)centrifugal compressor manufactured by the Dresser-Rand Company ofOlean, New York. The compressor 102 may have a center-hung rotorconfiguration or an overhung rotor configuration, as illustrated inFIG. 1. In an exemplary embodiment, the compressor 102 may be anaxial-inlet centrifugal compressor. In another embodiment, thecompressor 102 may be a radial-inlet centrifugal compressor. Aspreviously discussed, the compression system 100 may include one or morecompressors 102. For example, the compression system 100 may include aplurality of compressors (not shown). In another example, illustrated inFIG. 1, the compression system 100 may include a single compressor 102.The compressor 102 may be a supersonic compressor or a subsoniccompressor. In at least one embodiment, the compression system 100 mayinclude a plurality of compressors (not shown), and at least onecompressor of the plurality of compressors is a subsonic compressor. Inanother embodiment, illustrated in FIG. 1, the compression system 100includes a single compressor 102, and the single compressor 102 is asupersonic compressor.

The compressor 102 may include one or more stages (not shown). In atleast one embodiment, the compressor 102 may be a single-stagecompressor. In another embodiment, the compressor 102 may be amulti-stage centrifugal compressor. Each stage (not shown) of thecompressor 102 may be a subsonic compressor stage or a supersoniccompressor stage. In an exemplary embodiment, the compressor 102 mayinclude a single supersonic compressor stage. In another embodiment, thecompressor 102 may include a plurality of subsonic compressor stages. Inyet another embodiment, the compressor 102 may include a subsoniccompressor stage and a supersonic compressor stage. Any one or morestages of the compressor 102 may have a compression ratio greater thanabout 1:1. For example, any one or more stages of the compressor 102 mayhave a compression ratio of about 1.1:1, about 1.2:1, about 1.3:1, about1.4:1, about 1.5:1, about 1.6:1, about 1.7:1, about 1.8:1, about 1.9:1,about 2:1, about 2.1:1, about 2.2:1, about 2.3:1, about 2.4:1, about2.5:1, about 2.6:1, about 2.7:1, about 2.8:1, about 2.9:1, about 3:1,about 3.1:1, about 3.2:1, about 3.3:1, about 3.4:1, about 3.5:1, about3.6:1, about 3.7:1, about 3.8:1, about 3.9:1, about 4:1, about 4.1:1,about 4.2:1, about 4.3:1, about 4.4:1, about 4.5:1, about 4.6:1, about4.7:1, about 4.8:1, about 4.9:1, about 5:1, about 5.1:1, about 5.2:1,about 5.3:1, about 5.4:1, about 5.5:1, about 5.6:1, about 5.7:1, about5.8:1, about 5.9:1, about 6:1, about 6.1:1, about 6.2:1, about 6.3:1,about 6.4:1, about 6.5:1, about 6.6:1, about 6.7:1, about 6.8:1, about6.9:1, about 7:1, about 7.1:1, about 7.2:1, about 7.3:1, about 7.4:1,about 7.5:1, about 7.6:1, about 7.7:1, about 7.8:1, about 7.9:1, about8.0:1, about 8.1:1, about 8.2:1, about 8.3:1, about 8.4:1, about 8.5:1,about 8.6:1, about 8.7:1, about 8.8:1, about 8.9:1, about 9:1, about9.1:1, about 9.2:1, about 9.3:1, about 9.4:1, about 9.5:1, about 9.6:1,about 9.7:1, about 9.8:1, about 9.9:1, about 10:1, about 10.1:1, about10.2:1, about 10.3:1, about 10.4:1, about 10.5:1, about 10.6:1, about10.7:1, about 10.8:1, about 10.9:1, about 11:1, about 11.1:1, about11.2:1, about 11.3:1, about 11.4:1, about 11.5:1, 11 3.6:1, about11.7:1, about 11.8:1, about 11.9:1, about 12:1, about 12.1:1, about12.2:1, about 12.3:1, about 12.4:1, about 12.5:1, about 12.6:1, about12.7:1, about 12.8:1, about 12.9:1, about 13:1, about 13.1:1, about13.2:1, about 13.3:1, about 13.4:1, about 13.5:1, about 13.6:1, about13.7:1, about 13.8:1, about 13.9:1, about 14:1, or greater. In anexemplary embodiment, the compressor 102 may include a plurality ofcompressor stages, where a first stage (not shown) of the plurality ofcompressor stages may have a compression ratio of about 1.75:1 and asecond stage (not shown) of the plurality of compressor stages may havea compression ratio of about 6.0:1.

FIG. 2 illustrates a cross-sectional view of an embodiment of thecompressor 102, which may be included in the compression system 100 ofFIG. 1. As shown in FIG. 2, the compressor 102 includes a housing 110forming or having an axial inlet 112 defining an inlet passageway 114, astatic diffuser 116 fluidly coupled to the inlet passageway 114, and acollector 117 fluidly coupled to the static diffuser 116. Althoughillustrated as an axial inlet in FIG. 2, in one or more otherembodiments, the inlet 112 may be a radial inlet. The driver 104 may bedisposed outside of (as shown in FIG. 1) or within the housing 110, suchthat the housing 110 may have a first end, or compressor end, and asecond end (not shown), or driver end. The housing 110 may be configuredto hermetically seal the driver 104 and the compressor 102 within,thereby providing both support and protection to each component of thecompression system 100. The housing 110 may also be configured tocontain the process fluid flowing through one or more portions orcomponents of the compressor 102.

The drive shaft 106 of the driver 104 and the rotary shaft 108 of thecompressor 102 may be supported, respectively, by one or more radialbearings 118, as shown in FIG. 1 in an overhung configuration. Theradial bearings 118 may be directly or indirectly supported by thehousing 110, and in turn provide support to the drive shaft 106 and therotary shaft 108, which carry the compressor 102 and the driver 104during operation of the compression system 100. In one embodiment, theradial bearings 118 may be magnetic bearings, such as active or passivemagnetic bearings. In other embodiments, however, other types ofbearings (e.g., oil film bearings) may be used. In addition, at leastone axial thrust bearing 120 may be provided to manage movement of therotary shaft 108 in the axial direction. In an embodiment in which thedriver 104 and the compressor 102 are hermetically-sealed within thehousing 110, the axial thrust bearing 120 may be provided at or near theend of the rotary shaft 108 adjacent the compressor end of the housing110. The axial thrust bearing 120 may be a magnetic bearing and may beconfigured to bear axial thrusts generated by the compressor 102.

As shown in FIG. 2, the axial inlet 112 defining the inlet passageway114 of the compressor 102 may include one or more inlet guide vanes 122of an inlet guide vane assembly configured to condition a process fluidflowing therethrough to achieve predetermined or desired fluidproperties and/or fluid flow attributes. Such fluid properties mayinclude flow pattern (e.g., swirl distribution), velocity, mass flowrate, pressure, temperature, and/or any suitable fluid property andfluid flow attribute to enable the compressor 102 to function asdescribed herein. The inlet guide vanes 122 may be disposed within theinlet passageway 114 and may be static or moveable, i.e., adjustable. Inan exemplary embodiment, a plurality of inlet guide vanes 122 may bearranged about a circumferential inner surface 124 of the axial inlet112 in a spaced apart orientation, each extending into the inletpassageway 114. The spacing of the inlet guide vanes 122 may beequidistant or may vary depending on the predetermined process fluidproperty and/or fluid flow attribute desired. With reference to shape,the inlet guide vanes 122 may be airfoil shaped, streamline shaped, orotherwise shaped and configured to at least partially impart the one ormore fluid properties and/or fluid flow attributes on the process fluidflowing through the inlet passageway 114.

In one or more embodiments, the inlet guide vanes 122 may be moveablycoupled to the housing 110 and disposed within the inlet passageway 114as disclosed in U.S. Pat. No. 8,632,302, the subject matter of which isincorporated by reference herein to the extent consistent with thepresent disclosure. The inlet guide vanes 122 may be further coupled toan annular inlet guide vane actuation member (not shown), such that uponactuation of the annular inlet vane actuation member, each of the inletguide vanes 122 coupled to the annular inlet guide vane actuation membermay pivot about the respective coupling to the housing 110, therebyadjusting the flow incident on components of the compressor 102. Asconfigured, the inlet guide vanes 122 may be adjusted withoutdisassembling the housing 110 in order to adjust the performance of thecompressor 102. Doing so without disassembly of the compressor 102 savestime and effort in optimizing the compressor 102 for a particularoperating condition. Furthermore, the impact of alternate vane angles onoverall flow range and/or peak efficiency may be assessed and optimizedfor increased performance, and a matrix of inlet guide vane angles maybe produced on a relatively short cycle time relative to conventionalcompressors such that the data may be analyzed to determine the bestcombination of inlet guide vane angles for any given application.

The compressor 102 may include a centrifugal impeller 126 configured torotate about a center axis 128 within the housing 110. In an exemplaryembodiment, the centrifugal impeller 126 includes a hub 130 and is openor “unshrouded.” In another embodiment, the centrifugal impeller 126 maybe a shrouded impeller. The hub 130 may include a first meridional endportion 132, generally referred to as the eye of the centrifugalimpeller 126, and a second meridional end portion 134 having a discshape, the outer perimeter of the second meridional end portion 134generally referred to as the tip 136 of the centrifugal impeller 126.The disc-shaped, second meridional end portion 134 may taper inwardly tothe first meridional end portion 132 having an annular shape. The hub130 may define a bore 138 configured to receive a coupling member 140,such as a tiebolt, to couple the centrifugal impeller 126 to the rotaryshaft 108. In another embodiment, the bore 138 may be configured toreceive the rotary shaft 108 extending therethrough.

As shown in FIG. 2, the compressor 102 may include a balance piston 142configured to balance an axial thrust generated by the centrifugalimpeller 126 during operation. In an exemplary embodiment, the balancepiston 142 may be integral with the centrifugal impeller 126, such thatthe balance piston 142 and the centrifugal impeller 126 are formed froma single or unitary piece. In another embodiment, the balance piston 142and the centrifugal impeller 126 may be separate components. Forexample, the balance piston 142 and the centrifugal impeller 126 may beseparate annular components coupled with one another. One or more seals,e.g., labyrinth seals, may be implemented to isolate the balance piston142 from external contaminants or lubricants.

The centrifugal impeller 126 may be operatively coupled to the rotaryshaft 108 such that the rotary shaft 108, when acted upon by the driver104 via the drive shaft 106, rotates, thereby causing the centrifugalimpeller 126 to rotate such that process fluid flowing into the inletpassageway 114 is drawn into the centrifugal impeller 126 andaccelerated to the tip 136, or periphery, of the centrifugal impeller126, thereby increasing the velocity of the process fluid. In one ormore embodiments, the process fluid at the tip 136 of the centrifugalimpeller 126 may be subsonic and have an absolute Mach number less thanone. For example, the process fluid at the tip 136 of the centrifugalimpeller 126 may have an exit absolute Mach number less than one, lessthan 0.9, less than 0.8, less than 0.7, less than 0.6, or less than 0.5.Accordingly, in such embodiments, the compressor 102 discussed hereinmay be “subsonic,” as the centrifugal impeller 126 may be configured torotate about the center axis 128 at a speed sufficient to provide theprocess fluid at the tip 136 thereof with an exit absolute Mach numberof less than one.

In one or more embodiments, the process fluid at the tip 136 of thecentrifugal impeller 126 may be supersonic and have an exit absoluteMach number of one or greater. For example, the process fluid at the tip136 of the centrifugal impeller 126 may have an exit absolute Machnumber of at least one, at least 1.1, at least 1.2, at least 1.3, atleast 1.4, or at least 1.5. Accordingly, in such embodiments, thecompressor 102 discussed herein may be “supersonic,” as the centrifugalimpeller 126 may be configured to rotate about the center axis 128 at aspeed sufficient to provide the process fluid at the tip 136 thereofwith an exit absolute Mach number of one or greater or with a fluidvelocity greater than the speed of sound. In a supersonic compressor ora stage thereof, the rotational or tip speed of the centrifugal impeller126 may be about 500 meters per second (mis) or greater. For example,the tip speed of the centrifugal impeller 126 may be about 510 m/s,about 520 m/s, about 530 m/s, about 540 m/s, about 550 m/s, about 560m/s, or greater.

Referring now to FIGS. 3A and 3B, with continued reference to FIG. 2,FIGS. 3A and 3B illustrate a perspective view and a front view,respectively, of the centrifugal impeller 126 that may be included inthe compressor 102, according to one or more embodiments. As shown inFIG. 2 and more clearly in FIGS. 3A and 3B, the centrifugal impeller 126may include a plurality of aerodynamic surfaces or blades 144 a,bcoupled or integral with the hub 130 and configured to increase thevelocity and energy of the process fluid. As illustrated in FIGS. 3A and3B, the blades 144 a,b of the centrifugal impeller 126 may be curved,such that the process fluid may be urged in a tangential and radialdirection by the centrifugal force through a plurality of flow passages146, 148 formed by the blades 144 a,b and discharged from the blade tipsof the centrifugal impeller 126 (cumulatively, the tip 136 of thecentrifugal impeller 126) in at least partially radial directions thatextend 360 degrees around the centrifugal impeller 126. It will beappreciated that the contour or amount of curvature of the blades 144a,b is not limited to the shaping illustrated in FIGS. 3A and 3B and maybe determined based, at least in part, on desired operating parameters.

The plurality of blades 144 a,b may include main blades 144 a spacedequidistantly apart and circumferentially about the center axis 128.Each main blade 144 a may extend from a leading edge 150 disposedadjacent the first meridional end portion 132 of the centrifugalimpeller 126 to a trailing edge 152 disposed adjacent the secondmeridional end portion 134 of the centrifugal impeller 126. Further,based on rotation of the centrifugal impeller 126, each main blade 144 amay define a pressure surface on one side 154 of the main blade 144 aand a suction surface on the opposing side 156 of the main blade 1144 a.As shown in FIGS. 3A and 3B, the centrifugal impeller 126 may includethirteen main blades 144 a; however, other embodiments including morethan or less than thirteen main blades 144 a are contemplated herein.The number of main blades 144 a may be determined based, at least inpart, on desired operating parameters.

The plurality of blades 144 a,b may also include one or more splitterblades 144 b configured to reduce aerodynamic choking conditions thatmay occur in the compressor 102 depending on the number of blades 144a,b employed with respect to the centrifugal impeller 126. The splitterblades 144 b may be spaced equidistantly apart and circumferentiallyabout the center axis 128. Each splitter blade 144 b may extend from aleading edge 158, meridionally spaced and downstream from the firstmeridional end portion 132, to a trailing edge 160 disposed adjacent thesecond meridional end portion 134 of the centrifugal impeller 126. Theleading edge 158 of each splitter blade 144 b may be disposedmeridionally outward from the leading edges 150 of the main blades 144 asuch that the respective leading edges 150, 158 of the main blades 144 aand splitter blades 144 b are staggered and not coplanar. Further, basedon rotation of the centrifugal impeller 126, each splitter blade 144 bmay define a pressure surface on one side 162 of the splitter blade 144b and a suction surface on the opposing side 164 of the splitter blade144 b.

As most clearly illustrated in FIGS. 2 and 3A, each of the main blades144 a and the splitter blades 144 b extends meridionally from the secondmeridional end portion 134 of the centrifugal impeller 126 toward thefirst meridional end portion 132 thereof. The configuration of therespective meridional extents of the main blades 144 a and the splitterblades 144 b may be substantially similar proximal the respectivetrailing edges 152, 160 of the main blades 144 a and the splitter blades144 b. The configuration of the respective meridional extents of themain blades 144 a and the splitter blades 144 b may differ from thesecond meridional end portion 134 to the respective leading edges 150,158 of the main blades 144 a and the splitter blades 144 b. In anexemplary embodiment, the meridional extent of each of the main blades144 a may be greater than the meridional extent of each of the splitterblades 144 b, such that the respective leading edges 158 of the splitterblades 144 b may be disposed meridionally offset toward the secondmeridional end portion 134 of the centrifugal impeller 126 from therespective leading edges 150 of the main blades 144 a.

The splitter blades 144 b and main blades 144 a may be arrangedcircumferentially about the center axis 128 in a pattern such that asplitter blade 144 b is disposed between adjacent main blades 144 a. Asarranged, each splitter blade 144 b may be disposed between the pressuresurface side 154 of an adjacent main blade 144 a and the suction surfaceside 156 of the other adjacent main blade 144 a. Further, the splitterblades 144 b may be “clocked” with respect to the main blades 144 a,such that each splitter blade 144 b is circumferentially offset or notequidistant from the respective adjacent main blades 144 a and thus isnot circumferentially centered between the adjacent main blades 144 a.By clocking the splitter blades 144 b, e.g., displacing the splitterblades 144 b from a position equidistant from the adjacent main blades144 a, the operating characteristics of the centrifugal impeller 126 maybe improved.

In one or more embodiments, the splitter blades 144 b and main blades144 a may be arranged circumferentially about the center axis 128 in apattern such that a plurality of splitter blades 144 b may be disposedbetween adjacent main blades 144 a. Accordingly, in one embodiment, atleast two splitter blades 144 b are disposed between adjacent mainblades 144 a. The leading edges 158 of the respective splitter blades144 b may be offset meridionally from one another such that therespective leading edges 158 of the splitter blades 144 b are staggeredand not coplanar.

As positioned between the adjacent main blades 144 a, each splitterblade 144 b may be oriented such that the splitter blade 144 b iscanted, such that the leading edge 158 of the splitter blade 144 b iscircumferentially offset from a position equidistant from the adjacentmain blades 144 a a different percentage amount than the trailing edge160 of the splitter blade 144 b. Accordingly, in an exemplaryembodiment, the leading edge 158 of the splitter blade 144 b may bedisplaced from a position equidistant from the adjacent main blades 144a by a distance of a first percentage amount of one half the angulardistance θ between the adjacent main blades 144 a. The trailing edge 160of the splitter blade 144 b may be displaced from the positionequidistant the adjacent main blades 144 a by a distance of a secondpercentage amount of one half the angular distance 8 between theadjacent main blades 144 a.

In an exemplary embodiment, the first percentage amount may be greaterthan the second percentage amount. In another embodiment, the firstpercentage amount may be less than the second percentage amount. Forexample, the difference in displacement between the leading edge 158 andthe trailing edge 160 from the position equidistant the adjacent mainblades 144 a may be a percentage amount of at least about one percent,about two percent, about three percent, about four percent, about fivepercent, about ten percent, about fifteen percent, or about twentypercent. In another example, the difference in displacement between theleading edge 158 and the trailing edge 160 from the position equidistantthe adjacent main blades 144 a may be a percentage amount of betweenabout one percent and about two percent, about three percent and aboutfive percent, about five percent and about ten percent, or about tenpercent and about twenty percent. The differences in distance related tothe percentage amounts, e.g., the amount the splitter blade 144 b iscanted, may be determined based, at least in part, on desired operatingparameters.

As shown in FIGS. 3A and 3B, a plurality of flow passages 146, 148 maybe formed between the splitter blades 144 b and the adjacent main blades144 a as arranged about the center axis 128. In an exemplary embodiment,the plurality of flow passages 146, 148 may include a first flow passage146 formed between the pressure surface side 162 of the splitter blade144 b and the suction surface side 156 of one of the adjacent mainblades 144 a and a second flow passage 148 between the suction surfaceside 164 of the splitter blade 144 b and the pressure surface side 154of the other adjacent main blade 144 a. The mass flow of the processfluid through the first and second flow passages 146, 148 may bedetermined based on the displacement of the splitter blade 144 b inrelation to the adjacent main blades 144 a. For example, it has beendetermined that disposing the splitter blade 144 b equidistantly betweenthe adjacent main blades 144 a may not result in equal mass flow throughthe first flow passage 146 and the second flow passage 148. Accordingly,in an exemplary embodiment, the splitter blade 144 b may becircumferentially offset from a position centered between adjacent mainblades 144 a, such that the suction surface side 164 of the splitterblade 144 b is disposed in a direction closer to the pressure surfaceside 154 of one of the adjacent main blades 144 a and further from thesuction surface side 156 of the other adjacent main blade 144 a, therebysubstantially equalizing the mass flow through the respective flowpassages 146, 148.

As will be appreciated by those of skill in the art, the desireddisplacement of the splitter blades 144 b may depend on various factors,such as the shape of the blades 144 a,b, the angle of incidence of theblades 144 a,b, the size of the blades 144 a,b and of the centrifugalimpeller 126, the operating speed range, etc. However, the displacementnecessary to equalize the mass flow through the first flow passage 146and the second flow passage 148 may be determined for a given design ofthe centrifugal impeller 126 and corresponding blades 144 a,b bymeasurement of the mass flow, such as by use of a mass flow meter.

As shown in FIG. 2, the compressor 102 may include a shroud 170 coupledto the housing 110 and disposed adjacent the plurality of blades 144 a,bof the centrifugal impeller 126. In particular, a surface 172 of theshroud 170 may include an abradable material and may be contoured tosubstantially align with the silhouette of the plurality of blades 144a,b, thus substantially reducing leakage flow of the process fluid in agap defined therebetween. The abradable material is arranged on thesurface 172 of the shroud 170 and configured to be deformed and/orremoved therefrom during incidental contact of the rotating centrifugalimpeller 126 with the abradable material of the stationary shroud 170during axial movement of the rotary shaft 108, thereby preventing damageto the blades 144 a,b and resulting in a loss of a sacrificial amount ofthe abradable material.

In an embodiment, illustrated most clearly in FIG. 2, the compressor 102may include the static diffuser 116 fluidly coupled to the axial inlet112 and configured to receive the radial process fluid flow exiting thetip 136 of the centrifugal impeller 126. As shown in FIG. 2, the staticdiffuser 116 may be a vaneless diffuser. The static diffuser 116 may beconfigured to convert kinetic energy of the process fluid from thecentrifugal impeller 126 into increased static pressure. In an exemplaryembodiment, the static diffuser 116 may be located downstream of thecentrifugal impeller 126 and may be statically disposedcircumferentially about the periphery, or tip 136, of the centrifugalimpeller 126.

The static diffuser 116 may be coupled with or integral with the housing110 of the compressor 102 and may form an annular diffuser passageway174 having an inlet end adjacent the tip 136 of the centrifugal impeller126 and a radially outer outlet end. In an exemplary embodiment, theannular diffuser passageway 174 may be formed, at least in part, byportions of the housing 110, namely a shroud wall 180 and a hub wall182, forming the confining sidewalls of the static diffuser 116. Theshroud wall 180 and the hub wall 182 may each be a straight wall or acontoured wall, such that the annular diffuser passageway 174 may beformed from straight walls, contoured walls, or a combination thereof.In addition, the annular diffuser passageway 174 may have a reducedwidth as the shroud wall 180 and the hub wall 182 extend radiallyoutward. Such a “pinched” diffuser may provide for lower choke and surgelimits and, thus, improve the efficiency of the centrifugal impeller126.

In another embodiment, the static diffuser 116 may be a vaned diffuser.Accordingly, the static diffuser 116 may have a plurality of diffuservanes (not shown) arranged in a plurality of concentric rings (notshown) about the center axis 128 and extending from the shroud wall 180and/or the hub wall 182 of the static diffuser 116. In an exemplaryembodiment, the diffuser vanes are arranged in tandem, such that a firstring of diffuser vanes is disposed radially inward from a second ring ofdiffuser vanes. Respective leading edges of the diffuser vanes of thesecond ring may be displaced radially outward from trailing edges of thediffuser vanes of the first ring. The diffuser vanes of the first ringmay have a lower solidity, or chord to pitch ratio, than the diffuservanes of the second ring. In another embodiment, the static diffuser mayinclude a third ring of diffuser vanes, wherein the diffuser vanes ofthe third ring may have a lower solidity than the diffuser vanes of thesecond ring. Each of the diffuser vanes may be airfoils or shapedsubstantially similar thereto.

A vaneless space (not shown) may be provided between the tip 136 of thecentrifugal impeller 126 and the diameter formed by leading edges of thediffuser vanes of the first ring. Similarly, a vaneless space (notshown) may be provided between the diameter formed by the trailing edgesof the diffuser vanes of the first ring and the leading edges of thediffuser vanes of the second ring. In one or more embodiments, theincidence of the diffuser vanes of the first ring may be determined forcontrolling the Mach number and reducing supersonic flow introduced atthe inlet end of the static diffuser 116 to a subsonic flow at thetrailing edges of the first ring. As configured, shock waves created bythe leading edges of the first ring do not propagate to the diffuservanes of the second ring; however, the leading edges of the first ringprovide for a communication path from the downstream portion of thestatic diffuser 116 toward an upstream portion of the centrifugalimpeller 126 to back pressure the centrifugal impeller 126, therebyobtaining a wider range. The incidence of the diffuser vanes of thesecond ring may be determined by placing the second ring in the “shadow”or flow path of the first ring. Accordingly, the diffuser vanes may bearranged such that two diffuser vanes of the second ring are provided inthe wake of each diffuser vane of the first ring and are provided toalter the direction of the process fluid flow.

As discussed above, in one or more embodiments, the compressor 102provided herein may be referred to as “supersonic” because thecentrifugal impeller 126 may be designed to rotate about the center axis128 at high speeds such that a moving process fluid encountering theinlet end 176 of the static diffuser 116 is said to have a fluidvelocity which is above the speed of sound of the process fluid beingcompressed. Thus, in an exemplary embodiment, the moving process fluidencountering the inlet end 176 of the static diffuser 116 may have anexit absolute Mach number of about one or greater. However, to increasetotal energy of the fluid system, the moving process fluid encounteringthe inlet end 176 of the static diffuser 116 may have an exit absoluteMach number of at least about 1.1, at least about 1.2, at least about1.3, at least about 1.4, or at least about 1.5. In another example, theprocess fluid at the tip 136 of the centrifugal impeller 126 may have anexit absolute Mach number from about 1.1 to about 1.5, or about 1.2 toabout 1.4.

The process fluid flow leaving the outlet end of the static diffuser 116may flow into the collector 117, as most clearly seen in FIG. 2. Thecollector 117 may be configured to gather the process fluid flow fromthe static diffuser 116 and to deliver the process fluid flow to adownstream pipe and/or process component (not shown). In an exemplaryembodiment, the collector 117 may be a discharge volute or specifically,a scroll-type discharge volute. In another embodiment, the collector 117may be a plenum. The collector 117 may be further configured to increasethe static pressure of the process fluid flow by converting the kineticenergy of the process fluid to static pressure. The collector 117 mayhave a round tongue (not shown). In another embodiment, the collectormay have a sharp tongue (not shown). It will be appreciated that thetongue of the collector 117 may form other shapes known to those ofordinary skill in the art without varying from the scope of thisdisclosure.

One or more exemplary operational aspects of the compression system 100will now be discussed with continued reference to FIGS. 1-3B. A processfluid may be provided from an external source (not shown), having a lowpressure environment, to the compression system 100. The compressionsystem 100 may include, amongst other components, the compressor 102having the centrifugal impeller 126 coupled with the rotary shaft 108and the static diffuser 116 disposed circumferentially about therotating centrifugal impeller 126. The process fluid may be drawn intothe axial inlet 112 of the compressor 102 with a velocity ranging, forexample, from about Mach 0.05 to about Mach 0.40. The process fluid mayflow through the inlet passageway 114 defined by the axial inlet 112 andacross the inlet guide vanes 122 extending into the inlet passageway114. The process fluid flowing across the inlet guide vanes 122 may beprovided with an increased velocity and imparted with at least one fluidproperty (e.g., swirl) prior to be being drawn into the rotatingcentrifugal impeller 126. The inlet guide vanes 122 may be adjusted inorder to vary the one or more fluid properties imparted to the processfluid.

The process fluid may be drawn into the rotating centrifugal impeller126 and may contact the curved centrifugal impeller blades 144 a,b, suchthat the process fluid may be accelerated in a tangential and radialdirection by centrifugal force through the first flow passages 146 andthe second flow passages 148 and may be discharged from the blade tipsof the centrifugal impeller 126 (cumulatively, the tip 136 of thecentrifugal impeller 126) in at least partially radial directions thatextend 360 degrees around the rotating centrifugal impeller 126. Therotating centrifugal impeller 126 increases the velocity and staticpressure of the process fluid, such that the velocity of the processfluid discharged from the blade tips (cumulatively, the tip 136 of thecentrifugal impeller 126) may be supersonic in some embodiments and havean exit absolute Mach number of at least about one, at least about 1.1,at least about 1.2, at least about 1.3, at least about 1.4, or at leastabout 1.5.

The static diffuser 116 may be disposed circumferentially about theperiphery, or tip 136, of the centrifugal impeller 126 and may becoupled with or integral with the housing 110 of the compressor 102. Theradial process fluid flow discharged from the rotating centrifugalimpeller 126 may be received by the static diffuser 116 such that thevelocity of the flow of process fluid discharged from the tip 136 of therotating centrifugal impeller 126 is substantially similar to thevelocity of the process fluid entering the inlet end of the staticdiffuser 116. Accordingly, the process fluid may enter the inlet end ofthe static diffuser 116 with a supersonic velocity having, for example,an exit absolute Mach number of at least one, and correspondingly, maybe referred to as supersonic process fluid.

The velocity of the supersonic process fluid flowing into the inlet endof the static diffuser 116 decreases with increasing radius of theannular diffuser passageway 174 as the process fluid flows from theinlet end to the radially outer outlet end of the static diffuser 116 asthe velocity head is converted to static pressure. In some embodiments,the tangential velocity of the supersonic process fluid may deceleratefrom supersonic to subsonic velocities across the diffuser vanes of thefirst ring without shock losses. Accordingly, the static diffuser 116may reduce the velocity and increase the pressure energy of the processfluid.

The process fluid exiting the static diffuser 116 may have a subsonicvelocity and may be fed into the collector 117 or discharge volute. Thecollector 117 may increase the static pressure of the process fluid byconverting the remaining kinetic energy of the process fluid to staticpressure. The process fluid may then be routed to perform work or foroperation of one or more downstream processes or components (not shown).

The process fluid pressurized, circulated, contained, or otherwiseutilized in the compression system 100 may be a fluid in a liquid phase,a gas phase, a supercritical state, a subcritical state, or anycombination thereof. The process fluid may be a mixture, or processfluid mixture. The process fluid may include one or more high molecularweight process fluids, one or more low molecular weight process fluids,or any mixture or combination thereof. As used herein, the term “highmolecular weight process fluids” refers to process fluids having amolecular weight of about 30 grams per mole (g/mol) or greater.Illustrative high molecular weight process fluids may include, but arenot limited to, hydrocarbons, such as ethane, propane, butanes,pentanes, and hexanes. Illustrative high molecular weight process fluidsmay also include, but are not limited to, carbon dioxide (CO₂) orprocess fluid mixtures containing carbon dioxide. As used herein, theterm “low molecular weight process fluids” refers to process fluidshaving a molecular weight less than about 30 g/mol. Illustrative lowmolecular weight process fluids may include, but are not limited to,air, hydrogen, methane, or any combination or mixtures thereof.

In an exemplary embodiment, the process fluid or the process fluidmixture may be or include carbon dioxide. The amount of carbon dioxidein the process fluid or the process fluid mixture may be at least about80%, at least about 85%, at least about 90%, at least about 95%, atleast about 96%, at least about 97%, at least about 98%, at least about99%, or greater by volume. Utilizing carbon dioxide as the process fluidor as a component or part of the process fluid mixture in thecompression system 100 may provide one or more advantages. For example,the high density and high heat capacity or volumetric heat capacity ofcarbon dioxide with respect to other process fluids may make carbondioxide more “energy dense.” Accordingly, a relative size of thecompression system 100 and/or the components thereof may be reducedwithout reducing the performance of the compression system 100.

The carbon dioxide may be of any particular type, source, purity, orgrade. For example, industrial grade carbon dioxide may be utilized asthe process fluid without departing from the scope of the disclosure.Further, as previously discussed, the process fluids may be a mixture,or process fluid mixture. The process fluid mixture may be selected forone or more desirable properties of the process fluid mixture within thecompression system 100. For example, the process fluid mixture mayinclude a mixture of a liquid absorbent and carbon dioxide (or a processfluid containing carbon dioxide) that may enable the process fluidmixture to be compressed to a relatively higher pressure with lessenergy input than compressing carbon dioxide (or a process fluidcontaining carbon dioxide) alone.

It should be appreciated that all numerical values and ranges disclosedherein are approximate valves and ranges, whether “about” is used inconjunction therewith. It should also be appreciated that the term“about,” as used herein, in conjunction with a numeral refers to a valuethat is +/−5% (inclusive) of that numeral, +/−10% (inclusive) of thatnumeral, or +/−15% (inclusive) of that numeral. It should further beappreciated that when a numerical range is disclosed herein, anynumerical value falling within the range is also specifically disclosed.

Certain embodiments and features have been described using a set ofnumerical upper limits and a set of numerical lower limits. It should beappreciated that ranges including the combination of any two values,e.g., the combination of any lower value with any upper value, thecombination of any two lower values, and/or the combination of any twoupper values are contemplated unless otherwise indicated.

The foregoing has outlined features of several embodiments so that thoseskilled in the art may better understand the present disclosure. Thoseskilled in the art should appreciate that they may readily use thepresent disclosure as a basis for designing or modifying other processesand structures for carrying out the same purposes and/or achieving thesame advantages of the embodiments introduced herein. Those skilled inthe art should also realize that such equivalent constructions do notdepart from the spirit and scope of the present disclosure, and thatthey may make various changes, substitutions and alterations hereinwithout departing from the spirit and scope of the present disclosure.

We claim:
 1. An impeller for a compressor, comprising: a hub mountableto a rotary shaft of the compressor and configured to rotate about acenter axis, the hub comprising a first meridional end portion and asecond meridional end portion; a plurality of main blades mounted to orintegral with the hub, the plurality of main blades arrangedequidistantly and circumferentially about the center axis; and aplurality of splitter blades mounted to or integral with the hub, theplurality of splitter blades arranged equidistantly andcircumferentially about the center axis, each splitter blade comprisinga leading edge meridionally spaced from the first meridional end portionand a trailing edge proximal the second meridional end portion, whereina splitter blade is positioned between a first adjacent main blade and asecond adjacent main blade and canted such that the leading edge of thesplitter blade is displaced from a blade position equidistant the firstadjacent main blade and the second adjacent main blade a firstpercentage amount of one half an angular distance between the firstadjacent main blade and the second adjacent main blade, and the trailingedge of the splitter blade is displaced from the blade positionequidistant the first adjacent main blade and the second adjacent mainblade a second percentage amount of one half the angular distancebetween the first adjacent main blade and the second adjacent mainblade, the second percentage amount being greater or less than the firstpercentage amount.
 2. The impeller of claim 1, wherein the splitterblade is positioned between the first adjacent main blade and the secondadjacent main blade such that the splitter blade is circumferentiallyoffset from the blade position equidistant the first adjacent main bladeand the second adjacent main blade.
 3. The impeller of claim 1, whereineach main blade of the plurality of main blades comprises: a leadingedge proximal the first meridional end portion; a trailing edge proximalthe second meridional end portion; a pressure surface side extendingbetween the leading edge and the trailing edge; and a suction surfaceside opposing the pressure surface side and extending between theleading edge and the trailing edge, wherein the splitter blade ispositioned between a pressure surface side of the first adjacent mainblade and a suction surface side of the second adjacent main blade suchthat the splitter blade is circumferentially offset from the bladeposition equidistant the first adjacent main blade and the secondadjacent main blade.
 4. The impeller of claim 3, wherein the splitterblade is circumferentially offset in a direction toward the pressuresurface side of the first adjacent main blade.
 5. The impeller of claim3, wherein: a first flow passage is formed between the splitter bladeand the pressure surface side of the first adjacent main blade; and asecond flow passage is formed between the splitter blade and the suctionsurface side of the second adjacent main blade, such that the first flowpassage and the second flow passage are configured to receivesubstantially equal mass flow therethrough.
 6. The impeller of claim 5,wherein the splitter blade comprises: a pressure surface side extendingbetween the leading edge and the trailing edge of the splitter blade;and a suction surface side opposing the pressure surface side andextending between the leading edge and the trailing edge of the splitterblade, wherein the first flow passage is formed between the suctionsurface side of the splitter blade and the pressure surface side of thefirst adjacent main blade, and the second flow passage is formed betweenthe pressure surface side of the splitter blade and the suction surfaceside of the second adjacent main blade.
 7. The impeller of claim 1,wherein the plurality of main blades and the plurality of splitterblades are equal in number.
 8. The impeller of claim 1, wherein therespective leading edges of the main blades and the respective leadingedges of the splitter blades are arranged in an meridionally-staggeredpattern with respect to one another.
 9. The impeller of claim 1, whereinthe splitter blade is positioned between the first adjacent main bladeand the second adjacent main blade and canted such that the secondpercentage amount is greater than the first percentage amount.
 10. Theimpeller of claim 1, wherein the splitter blade is positioned betweenthe first adjacent main blade and the second adjacent main blade andcanted such that the second percentage amount is less than the firstpercentage amount.
 11. A compressor comprising: a housing; an inletcoupled to or integral with the housing and defining an inlet passagewayconfigured to receive and flow a process fluid; a rotary shaftconfigured to be driven by a driver; a centrifugal impeller coupled withthe rotary shaft and fluidly coupled to the inlet passageway, thecentrifugal impeller configured to rotate about a center axis and impartenergy to the process fluid received via the inlet passageway, thecentrifugal impeller comprising: a hub defining a borehole through whicha coupling member or the rotary shaft of the compressor extends, the hubcomprising a first meridional end portion having an annular portion anda second meridional end portion forming a disc-shaped portion; and aplurality of blades mounted to or integral with the hub, the pluralityof blades arranged equidistantly and circumferentially about the centeraxis and comprising a splitter blade positioned between a first adjacentmain blade and a second adjacent main blade and canted with respect tothe first adjacent main blade and the second adjacent main blade; astatic diffuser circumferentially disposed about the centrifugalimpeller and configured to receive the process fluid from thecentrifugal impeller and convert the energy imparted to pressure energy;and a collector fluidly coupled to and configured to collect the processfluid exiting the static diffuser, wherein the compressor is configuredto provide a compression ratio of at least about 8:1.
 12. The compressorof claim 11, wherein: the splitter blade comprises a leading edgemeridionally spaced from the first meridional end portion and a trailingedge proximal the second meridional end portion, and the splitter bladeis positioned between the first adjacent main blade and the secondadjacent main blade and canted such that the leading edge of thesplitter blade is displaced from a blade position equidistant the firstadjacent main blade and the second adjacent main blade a firstpercentage amount of one half an angular distance between the firstadjacent main blade and the second adjacent main blade, and the trailingedge of the splitter blade is displaced from the blade positionequidistant the first adjacent main blade and the second adjacent mainblade a second percentage amount of one half the angular distancebetween the first adjacent main blade and the second adjacent mainblade, the second percentage amount being greater or less than the firstpercentage amount.
 13. The compressor of claim 11, wherein the splitterblade is positioned between the first adjacent main blade and the secondadjacent main blade such that the splitter blade is circumferentiallyoffset from the blade position equidistant the first adjacent main bladeand the second adjacent main blade.
 14. The compressor of claim 11,wherein each main blade of the plurality of main blades comprises: aleading edge proximal the first meridional end; a trailing edge proximalthe second meridional end; a pressure surface side extending from theleading edge to the trailing edge; and a suction surface side opposingthe pressure surface side and extending from the leading edge to thetrailing edge, wherein the splitter blade is positioned between apressure surface side of the first adjacent main blade and a suctionside surface of the second adjacent main blade such that the splitterblade is circumferentially offset from the blade position equidistantthe first adjacent main blade and the second adjacent main blade. 15.The compressor of claim 14, wherein the splitter blade iscircumferentially offset in a direction toward the pressure surface sideof the first adjacent main blade.
 16. The compressor of claim 14,wherein: a first flow passage is formed between the splitter blade andthe pressure surface side of the first adjacent main blade; and a secondflow passage is formed between the splitter blade and the suctionsurface side of the second adjacent main blade, such that the first flowpassage and the second flow passage are configured to receivesubstantially equal mass flow therethrough.
 17. The compressor of claim11, wherein: the process fluid comprises carbon dioxide; the compressoris configured to provide a compression ratio of at least about 10:1; andthe second meridional end portion of the centrifugal impeller isconfigured to discharge the process fluid therefrom in at least apartially radial direction at an absolute Mach number of about 1.3 orgreater.
 18. The compressor of claim 17, wherein the centrifugalimpeller is configured to rotate via the rotary shaft at a rotationalspeed of about 500 meters per second or greater.
 19. A compressionsystem comprising: a driver comprising a drive shaft, the driverconfigured to provide the drive shaft with rotational energy; asupersonic compressor operatively coupled to the driver via a rotaryshaft integral with or coupled with the drive shaft and configured torotate about a center axis, the supersonic compressor comprising: acompressor chassis; an inlet defining an inlet passageway configured toflow a process fluid therethrough, the process fluid having a firstvelocity and a first pressure energy; a centrifugal impeller coupledwith the rotary shaft and fluidly coupled to the inlet passageway, thecentrifugal impeller having a tip and configured to increase the firstvelocity and the first pressure energy of the process fluid received viathe inlet passageway and discharge the process fluid from the tip in atleast a partially radial direction having a second velocity and a secondpressure energy, the second velocity being a supersonic velocity havingan absolute Mach number of about one or greater, wherein the centrifugalimpeller comprises: a hub defining a borehole through which a couplingmember or the rotary shaft of the supersonic compressor extends, the hubcomprising a first meridional end portion having an annular portion anda second meridional end portion forming the tip; and a plurality ofblades mounted to or integral with the hub, the plurality of bladesarranged equidistantly and circumferentially about the center axis andcomprising a splitter blade positioned between a first adjacent mainblade and a second adjacent main blade and canted with respect to thefirst adjacent main blade and the second adjacent main blade; a staticdiffuser circumferentially disposed about the tip of the centrifugalimpeller and defining an annular diffuser passageway configured toreceive and reduce the second velocity of the process fluid to a thirdvelocity and increase the second pressure energy to a third pressureenergy, the third velocity being a subsonic velocity; and a dischargevolute fluidly coupled to the annular diffuser passageway and configuredto receive the process fluid flowing therefrom, wherein the supersoniccompressor is configured to provide a compression ratio of at leastabout 8:1.
 20. The compression system of claim 19, wherein: the processfluid comprises carbon dioxide; the second velocity has an absolute Machnumber of about 1.3 or greater; the supersonic compressor is configuredto provide a compression ratio of at least about 10:1; and the splitterblade is positioned between the first adjacent main blade and the secondadjacent main blade such that the splitter blade is circumferentiallyoffset from a blade position equidistant the first adjacent main bladeand the second adjacent main blade, the splitter blade beingcircumferentially offset in a direction toward a pressure surface sideof the first adjacent main blade.